TACONIC QUESTION IN GEOLOGY. D DA 
$ 13. The name of Hudson slates had already, in his fourth annual report on the 
Southern district of New York, been given by Mather to the strata which he regarded as 
equivalent to the Loraine shale; described by Emmons as occurring in Jefferson and Lewis 
counties, in the Northern district. These strata were farther studied by Vanuxem in the 
Central or intermediate district, which included the cotnties of Oswego, Oneida, Herkimer 
and Montgomery, extending south-eastward along the valley of the Mohawk. The rocks 
found in this district were first described by Conrad as dark shales (the Utica slates) suc- 
ceeded by fossiliferous lead-colored shales alternating with gray sandstones, well dis- 
played at and near Pulaski, in Oswego county. At the summit of these was a sandstone 
quarried for grindstones, and in Oneida county the series was overlaid by a quartzose 
conglomerate. These were at first called by Vanuxem (who succeeded Conrad in the 
charge of the survey of this district,) the Pulaski shales and sandstones, and they clearly 
correspond to the Loraine shale and the Gray sandstone of Emmons. As these shales 
were also regarded, both by Emmons and by Vanuxem, as identical with the Hudson slates 
of Mather, Vanuxem included them in what he called the Hudson-River group ; a name 
which in subsequent geological and paleontological publications has generally replaced 
that of Loraine shale, as being synonymous with it. 
*  $14. The Hudson-River group, however, according to Vanuxem, embraced two distinct 
divisions, the upper, a highly fossiliferous member (being the Pulaski shales and sand- 
stone) found west of the Adirondacks, in Jefferson, Lewis and Pulaski counties, and dis- 
appearing to the south-eastward, in Oneida county. The lower member of the Hudson- 
River group, as defined by Vanuxem, was named the Frankfort division, from Frankfort 
in Herkimer county, and was described as consisting of greenish argillites and sandstones ; 
which underlie the Pulaski shales to the north-west, as far as Jefferson county, constitute 
in Herkimer and Montgomery counties, the only representative of the Hudson-River 
group; and extend eastward through Schenectady, Albany and Saratoga counties to the 
Hudson River. This lower division of the group was said to contain none of the organic 
remains of the Pulaski or upper division, but to include some graptolitic shales. To this 
lower division, Vanuxem supposed, might belong the thick masses of contorted argilla- 
ceous strata, of “ controverted age”, along the Hudson valley. 
He farther remarked that the two divisions of the Hudson-River group “are not 
co-extensive with each other. The lower one enters from the Southern district, along the 
Mohawk, and extends north by Rome, through Lewis into Jefferson county. The upper 
division first appear in Oneida county, and from thence west and north, is a co-associate of 
the Frankfort slate or lower division.” These two divisions, Vanuxem insisted on treating 
separately, “inclining to the opinion that they ought not to be put together in local 
geology.” * He, moreover, declared that the two divisions, although in juxtaposition in 
parts of New York, occur separately in Pennsylvania. The Pulaski shales, having in 
all respect the same characters as in New York, it was said, are found in the Nippenose 
valley, west of the Susquehanna; while the Frankfort slates and sandstones are seen to 
the east of the North Mountain, in the Kittatinny or Appalachian valley, and include the 
roofing-slates of the Delaware. 
The Oneida conglomerate, which in Oneida, New York, according to Vanuxem, rests 

* Geology of the Third district of New York, pp. 60-67, 
